Tom Donaly wrote:
Do you really believe that an antenna + loading coil has
to be a quarter wave long to resonate?
Note: I am NOT talking about *physical* lengths.
The phase shift from feedpoint to tip has to be
*electrically 90 degrees* so the answer is yes.
For a base-loaded mobile antenna, the sum of the
phase shifts a
PS1. The phase shift through the loading coil.
PS2. The phase shift at the coil to stinger junction.
PS3. The phase shift in the stinger.
PS1 + PS2 + PS3 = 90 degrees.
In a typical 75m base-loaded mobile antenna, PS1
may be about 40 degrees, PS2 about 40 degrees, and
PS3 about 10 degrees.
PS2 is a freebie lossless phase shift compliments of
Mother Nature caused by the impedance discontinuity
between the coil and the stinger. If that phase shift
can be maximized, it should add to antenna efficiency.
--
73, Cecil
http://www.w5dxp.com